In the past, land has been cleared for agricultural, industrial and housing purposes by removing tree stumps and tree roots. Large tractors have been used to remove tree stumps and roots from the ground. After removal from the ground, tree stumps and roots have been piled for burning, or they have been hauled away for disposal. Disposal at a remote location has been by burial, or by burning.
Environmental concerns, government requirements and cost have made it necessary to find other methods for clearing land. One method for land clearing is to grind tree stumps and roots into a mulch and leave the mulch in the ground where the tree stumps and roots were originally. This procedure eliminates transportation costs and disposal costs. Leaving a ground wood mulch on the ground improves soil fertility.
Tree stump grinders have been used to grind tree stumps following the removal of a tree from areas near buildings or other areas where it is desirable to minimize disturbance of the surface. Some of these stump grinders and other prior structures are disclosed in the following patents:
______________________________________ 3,198,224 Hiley 3,389,726 Good 3,868,980 Blum 3,937,261 Blum 3,931,841 Blum 4,041,996 Grover 4,339,908 Johnson ______________________________________
The prior stump machines generally comminute the portion of a stump that is above the ground and the portions which are near the surface. They grind up sufficient material to allow soil to cover the remaining stump and for grass to be planted. Such stump grinders generally do not remove all of a stump or tree roots. Stump grinders designed to grind the portion of a stump that is close to the surface are relatively slow.
The stump grinder disclosed by Grover was designed for land clearing, but is believed to be operative for smaller stumps because its hydraulic motor supports the grinding drum. Stump grinders similar to those disclosed by the above mentioned patentees have, in my opinion, major drawbacks. The drawbacks I perceive include being difficult to control, having insufficient capacity for the size and cost of the machine, having poor durability requiring expensive repairs, the inability to efficiently locate and grind tree roots, and the predisposition to frequent failures when working in difficult conditions.